Example plans · 3 plans

ADU floor plans

An ADU (accessory dwelling unit) is a second, smaller home on the same lot: a backyard cottage, a guest house or a casita. The maximum size is set by your state and city, so check it before you draw; our three plans have 400 to 750 sq ft. See the adu floor plans below, drawn to scale and measured room by room.

Plans: 3; drawn to scale
Sizes: 400 to 750 sq ft; finished area, ANSI Z765

See the plans Open the first plan in the editor

Drawn Oct 2, 2026 · How we calculate · Example plans, not real addresses

Studio ADU, 400 sq ft

The plans

ADU floor plans, 3 examples

Each plan is drawn to scale and measured room by room. Open one in the editor and change it to fit your lot.

Studio ADU, 400 sq ft

A 20 × 20 ft square: one room to live and sleep in, a kitchen along the back and a full bathroom.

Finished area: 400 sq ft; 37 m² · ANSI Z765
Not counted: Nothing; all of it is finished space
Layout: studio, 1 bath; one floor

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Opens as your own plan with the same numbers. Save the drawing (PNG)

Studio ADU, 400 sq ft floor plan: 400 sq ft (37 m²) finished, studio, 1 bath · one floor, drawn to scale with every room labeled. — 20′ × 20′ outsideExample floor plan, not a construction drawing

Rooms · Studio ADU, 400 sq ft

Room areas, Studio ADU, 400 sq ft
Room	Floor	Sq ft	Counts as
Living and sleeping	Floor 1	222	Finished, counts
Kitchen	Floor 1	84	Finished, counts
Bath	Floor 1	50	Finished, counts
Finished area, ANSI Z765		400	outside the walls

1 bed ADU, 600 sq ft

Wide and shallow, so it fits at the back of a lot: a living room with a kitchen, a bedroom with a closet, and a bathroom.

Finished area: 600 sq ft; 56 m² · ANSI Z765
Not counted: Nothing; all of it is finished space
Layout: 1 bed, 1 bath; one floor

Open in the editor Download the plan file

Opens as your own plan with the same numbers. Save the drawing (PNG)

1 bed ADU, 600 sq ft floor plan: 600 sq ft (56 m²) finished, 1 bed, 1 bath · one floor, drawn to scale with every room labeled. — 30′ × 20′ outsideExample floor plan, not a construction drawing

Rooms · 1 bed ADU, 600 sq ft

Room areas, 1 bed ADU, 600 sq ft
Room	Floor	Sq ft	Counts as
Living room	Floor 1	166	Finished, counts
Kitchen	Floor 1	79	Finished, counts
Bath	Floor 1	45	Finished, counts
Bedroom	Floor 1	164	Finished, counts
Closet	Floor 1	37	Finished, counts
Storage	Floor 1	40	Finished, counts
Finished area, ANSI Z765		600	outside the walls

Casita with a covered porch, 750 sq ft

A one-bedroom casita under a flat roof, with a covered porch across the whole front and a laundry room big enough for storage.

Finished area: 750 sq ft; 70 m² · ANSI Z765
Not counted: 236 sq ft; listed apart, see below
Layout: 1 bed, 1 bath; one floor

236 sq ft porch or deck

Open in the editor Download the plan file

Opens as your own plan with the same numbers. Save the drawing (PNG)

Casita with a covered porch, 750 sq ft floor plan: 750 sq ft (70 m²) finished, 1 bed, 1 bath · one floor, drawn to scale with every room labeled. — 30′ × 25′ outsideExample floor plan, not a construction drawing

Rooms · Casita with a covered porch, 750 sq ft

Room areas, Casita with a covered porch, 750 sq ft
Room	Floor	Sq ft	Counts as
Living room	Floor 1	198	Finished, counts
Kitchen and dining	Floor 1	166	Finished, counts
Bedroom	Floor 1	139	Finished, counts
Bath	Floor 1	51	Finished, counts
Closet	Floor 1	31	Finished, counts
Laundry and storage	Floor 1	89	Finished, counts
Covered porch	Outside	236	Outside, not counted
Finished area, ANSI Z765		750	outside the walls

What counts

What counts in the square footage

A permit usually asks for the floor area in a fixed way, so we measure every plan the same way: finished area to the outside of the walls (ANSI Z765). The casita’s covered porch, 236 sq ft, is outside and listed apart.

Each room is measured inside its walls. The finished area of a house is measured to the outside of the exterior walls (ANSI Z765), so it is larger than the rooms added up.

Questions

Adu floor plans: questions

About these adu plans. Can’t find your answer? Send us a message.

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What is the maximum size an ADU can be?

It depends on your state and city, and the rules change. Check the current limit with your local planning office before you draw; then shrink or grow a plan here to fit it.

What are some good floor plans for an ADU that is 1000 square feet?

At 1,000 sq ft an ADU can have two bedrooms. Our 1,000 sq ft house plan is a good start: open it and change the rooms to fit your lot.

Can I change these plans?

Yes. Click Open in the editor under a plan and it opens as your own plan in the Squaremetry editor, with the same numbers as on this page. Move a wall and every area and the total update.

Is this a construction drawing?

No. This is an example floor plan, not a construction drawing. The Squaremetry team drew it for this page; it has no address. For a permit you need drawings from a qualified designer.

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ADU floor plans

ADU floor plans, 3 examples

Studio ADU, 400 sq ft

1 bed ADU, 600 sq ft

Casita with a covered porch, 750 sq ft

What counts in the square footage

Related plans and sizes

Adu floor plans: questions

Start with your first floor plan